text: In addition to the above-mentioned sonic or acoustic black holes that can be viewed as analogues of astrophysical black holes, physical objects bearing the same names also exist in Acoustic and Vibration Engineering, where they are used for sound absorption and for damping structural vibrations. The Acoustic Black Hole effect in such objects can be achieved by creating a gradual reduction of sound velocity in a waveguide or elastic wave velocity in a solid structure (e.g. flexural wave velocity in thin plates) with propagation distance. The required velocity reduction should follow a power-law function of the propagation distance, and the velocity at the end of the wave propagation path should be reduced to almost zero. Also, measures should be taken to insert a small amount of traditional sound or vibration absorbing materials in the area of very low propagation velocity. Under these conditions, the described sonic or acoustic black holes provide almost 100% absorption of the incident air-borne or structure-borne acoustic waves.